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* kxsd9.c simple support for the Kionix KXSD9 3D
* accelerometer.
*
* Copyright (c) 2008-2009 Jonathan Cameron <jic23@kernel.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* The i2c interface is very similar, so shouldn't be a problem once
* I have a suitable wire made up.
*
* TODO: Support the motion detector
* Uses register address incrementing so could have a
* heavily optimized ring buffer access function.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define KXSD9_REG_X 0x00
#define KXSD9_REG_Y 0x02
#define KXSD9_REG_Z 0x04
#define KXSD9_REG_AUX 0x06
#define KXSD9_REG_RESET 0x0a
#define KXSD9_REG_CTRL_C 0x0c
#define KXSD9_FS_MASK 0x03
#define KXSD9_REG_CTRL_B 0x0d
#define KXSD9_REG_CTRL_A 0x0e
#define KXSD9_READ(a) (0x80 | (a))
#define KXSD9_WRITE(a) (a)
#define KXSD9_STATE_RX_SIZE 2
#define KXSD9_STATE_TX_SIZE 2
/**
* struct kxsd9_state - device related storage
* @buf_lock: protect the rx and tx buffers.
* @us: spi device
* @rx: single rx buffer storage
* @tx: single tx buffer storage
**/
struct kxsd9_state {
struct mutex buf_lock;
struct spi_device *us;
u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
u8 tx[KXSD9_STATE_TX_SIZE];
};
#define KXSD9_SCALE_2G "0.011978"
#define KXSD9_SCALE_4G "0.023927"
#define KXSD9_SCALE_6G "0.035934"
#define KXSD9_SCALE_8G "0.047853"
/* reverse order */
static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 };
static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
{
int ret, i;
struct kxsd9_state *st = iio_priv(indio_dev);
bool foundit = false;
for (i = 0; i < 4; i++)
if (micro == kxsd9_micro_scales[i]) {
foundit = true;
break;
}
if (!foundit)
return -EINVAL;
mutex_lock(&st->buf_lock);
ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
if (ret < 0)
goto error_ret;
st->tx[0] = KXSD9_WRITE(KXSD9_REG_CTRL_C);
st->tx[1] = (ret & ~KXSD9_FS_MASK) | i;
ret = spi_write(st->us, st->tx, 2);
error_ret:
mutex_unlock(&st->buf_lock);
return ret;
}
static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
{
int ret;
struct kxsd9_state *st = iio_priv(indio_dev);
struct spi_transfer xfers[] = {
{
.bits_per_word = 8,
.len = 1,
.delay_usecs = 200,
.tx_buf = st->tx,
}, {
.bits_per_word = 8,
.len = 2,
.rx_buf = st->rx,
},
};
mutex_lock(&st->buf_lock);
st->tx[0] = KXSD9_READ(address);
ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
if (!ret)
ret = (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0);
mutex_unlock(&st->buf_lock);
return ret;
}
static IIO_CONST_ATTR(accel_scale_available,
KXSD9_SCALE_2G " "
KXSD9_SCALE_4G " "
KXSD9_SCALE_6G " "
KXSD9_SCALE_8G);
static struct attribute *kxsd9_attributes[] = {
&iio_const_attr_accel_scale_available.dev_attr.attr,
NULL,
};
static int kxsd9_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
int ret = -EINVAL;
if (mask == IIO_CHAN_INFO_SCALE) {
/* Check no integer component */
if (val)
return -EINVAL;
ret = kxsd9_write_scale(indio_dev, val2);
}
return ret;
}
static int kxsd9_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret = -EINVAL;
struct kxsd9_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = kxsd9_read(indio_dev, chan->address);
if (ret < 0)
goto error_ret;
*val = ret;
ret = IIO_VAL_INT;
break;
case IIO_CHAN_INFO_SCALE:
ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
if (ret < 0)
goto error_ret;
*val = 0;
*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
ret = IIO_VAL_INT_PLUS_MICRO;
break;
}
error_ret:
return ret;
};
#define KXSD9_ACCEL_CHAN(axis) \
{ \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.address = KXSD9_REG_##axis, \
}
static const struct iio_chan_spec kxsd9_channels[] = {
KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z),
{
.type = IIO_VOLTAGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.indexed = 1,
.address = KXSD9_REG_AUX,
}
};
static const struct attribute_group kxsd9_attribute_group = {
.attrs = kxsd9_attributes,
};
static int kxsd9_power_up(struct kxsd9_state *st)
{
int ret;
st->tx[0] = 0x0d;
st->tx[1] = 0x40;
ret = spi_write(st->us, st->tx, 2);
if (ret)
return ret;
st->tx[0] = 0x0c;
st->tx[1] = 0x9b;
return spi_write(st->us, st->tx, 2);
};
static const struct iio_info kxsd9_info = {
.read_raw = &kxsd9_read_raw,
.write_raw = &kxsd9_write_raw,
.attrs = &kxsd9_attribute_group,
.driver_module = THIS_MODULE,
};
static int kxsd9_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct kxsd9_state *st;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
spi_set_drvdata(spi, indio_dev);
st->us = spi;
mutex_init(&st->buf_lock);
indio_dev->channels = kxsd9_channels;
indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->info = &kxsd9_info;
indio_dev->modes = INDIO_DIRECT_MODE;
spi->mode = SPI_MODE_0;
spi_setup(spi);
kxsd9_power_up(st);
return iio_device_register(indio_dev);
}
static int kxsd9_remove(struct spi_device *spi)
{
iio_device_unregister(spi_get_drvdata(spi));
return 0;
}
static const struct spi_device_id kxsd9_id[] = {
{"kxsd9", 0},
{ },
};
MODULE_DEVICE_TABLE(spi, kxsd9_id);
static struct spi_driver kxsd9_driver = {
.driver = {
.name = "kxsd9",
},
.probe = kxsd9_probe,
.remove = kxsd9_remove,
.id_table = kxsd9_id,
};
module_spi_driver(kxsd9_driver);
MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
MODULE_LICENSE("GPL v2");
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